Flexible printing plates can be attached to the plate cylinder of rotary printing machines in various ways. Many such plate cylinders have a groove, placed at the circumference of the cylinder and extending axially with respect thereto. An acute angle is formed between the walls of the groove and the circumference of the cylinder, the groove receiving a clamping spring arrangement to clamp the ends of the printing plate in the groove, the printing plate being wrapped around the remainder of the circumference of the plate cyclinder. As described in the referenced application Ser. No. 260,686, filed May 5, 1981, now U.S. Pat. No. 4,376,414, by the inventors hereof and titled "Printing Plate Attachment Arrangement", a clamping spring arrangement is provided which has two spring portions with clamping elements extending along at least part of one wall of the groove. The clamping elements are slidably held by wedge-shaped pressurized clamping bodies, which can clamp the ends of the printing plate against the wall of the groove. The two ends of the plate, thus, being clamped against the wall of the groove, are securely held within the attachment arrangement since, upon rotation of the plate cylinder, the clamping force increases due to centrifugal force acting on the wedge-shaped clamping elements tending to push them radially outwardly and hence in ever tighter engagement with the outwardly converging walls of the groove.